U.S. patent number 4,081,898 [Application Number 05/683,366] was granted by the patent office on 1978-04-04 for method of manufacturing an electronic calculator utilizing a flexible carrier.
This patent grant is currently assigned to Texas Instruments Incorporated. Invention is credited to Galen F. Fritz, James B. Taylor, Jr..
United States Patent |
4,081,898 |
Taylor, Jr. , et
al. |
April 4, 1978 |
Method of manufacturing an electronic calculator utilizing a
flexible carrier
Abstract
Electronic calculators are manufactured by use of a flexible
insulative carrier, the carrier being a tape-like-plastic substrate
a single length of which is sufficient to manufacture a plurality
of the electronic calculators, wherein conductor patterns are
formed on the carrier, a keyboard is formed on the carrier using
selected portions of the aforementioned conductors as keyboard
switch contacts and semiconductor devices are interconnected with
selected conductors formed on the carrier.
Inventors: |
Taylor, Jr.; James B. (Plano,
TX), Fritz; Galen F. (Houston, TX) |
Assignee: |
Texas Instruments Incorporated
(Dallas, TX)
|
Family
ID: |
24721414 |
Appl.
No.: |
05/683,366 |
Filed: |
May 5, 1976 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
678103 |
Apr 19, 1976 |
|
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|
Current U.S.
Class: |
29/622; 174/254;
200/5A; 200/512; 29/593; 708/190 |
Current CPC
Class: |
G06F
3/0202 (20130101); H01H 13/702 (20130101); H01H
2207/016 (20130101); H01H 2229/008 (20130101); H01H
2229/018 (20130101); H01H 2229/028 (20130101); H01H
2229/034 (20130101); H01H 2229/038 (20130101); H01H
2229/05 (20130101); H01H 2231/002 (20130101); H01H
2239/01 (20130101); Y10T 29/49105 (20150115); Y10T
29/49004 (20150115) |
Current International
Class: |
G06F
3/02 (20060101); H01H 13/70 (20060101); H01H
13/702 (20060101); H01H 011/00 () |
Field of
Search: |
;29/622,624,625,626,627,628,593,577
;156/87,228,230,232,285,286,311,382
;200/1R,5R,5A,11R,11G,11H,11J,11K,11D,159B,166BH,17C ;340/365A
;179/9K |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: DiPalma; Victor A.
Attorney, Agent or Firm: Grossman; Rene' E. Comfort; James
T. Berg; Richard P.
Parent Case Text
This is a continuation in part of application Ser. No. 678,103
filed Apr. 19, 1976 now abandoned.
Claims
What is claimed:
1. A method of manufacturing an electronic calculator
comprising:
(a) forming a pattern of conducting stripes on a flexible
substrate;
(b) forming a plurality of indentations in said substrate
intersecting selected portions of said conducting stripes in said
pattern;
(c) folding a portion of said substrate back on itself to form a
keyboard utilizing the indentations and selected conducting stripes
as keyboard switches; and
(d) connecting a tape-mounted semiconducting device and a display
device to said flexible substrate.
2. The method of claim 1, wherein the pattern of conducting stripes
is formed on the flexible substrate by hot die stamping.
3. The method according to claim 1, wherein the flexible substrate
comprises polyester film.
4. The method according to claim 1, wherein the flexible substrate
comprises polyimide film.
5. The method according to claim 1, wherein the flexible substrate
includes a series of registration holes disposed along at least one
of the margins thereof.
6. The method according to claim 1, wherein the pattern of
conducting stripes is formed on the flexible substrate by
selectively screening a conductive ink on the flexible
substrate.
7. The method according to claim 1, wherein the plurality of
indentations are formed in the substrate by thermally stamping the
substrate.
8. The method according to claim 1, wherein the plurality of
indentations are formed in the substrate by vacuum forming.
9. The method according to claim 1 wherein a plurality of
substantially identical patterns of conducting stripes are formed
on the flexible substrate.
10. The method according to claim 9, further including the step of
separating said patterns including keyboards and semiconducting
devices one from another after the step of folding a portion of the
substrate back on itself.
11. The method according to claim 1, wherein the portions of the
substrate folded back contain at least one of the indentations
formed in the flexible substrate.
12. The method according to claim 1 wherein the display device
connected to the flexible substrate is also tape mounted.
13. The method according to claim 1, further including the step of
affixing an apertured insulating sheet to said substrate in areas
where said substrate is folded back upon itself.
14. The method according to claim 13 wherein said apertured
insulating sheet is affixed to said substrate by adhesive
bonding.
15. The method according to claim 1, wherein the semiconducting
devices and the display device are connected to the flexible
substrate by soldering the leads from said semiconducting device
and said display device is selected conducting stripes formed on
said flexible substrate.
16. The method according to claim 1, wherein said semiconducting
device and said display device are connected to said flexible
substrate by adhesively bonding the leads of said semiconducting
device and said display device to selected conducting stripes
formed on said flexible substrate using an electrically conductive
cement.
17. The method according to claim 1 further including the steps of
testing the partially assembled electronic calculator and of
marking partially assembled electronic calculators failing a
test.
18. A method of manufacturing an electronic calculator
comprising:
(a) forming a pattern of conducting stripes on a flexible
substrate;
(b) forming another pattern of conducting stripes on an insulating
sheet;
(c) forming a plurality of indentations in at least one of said
substrate and said sheet, said indentations intersecting selected
portions of said conducting stripes;
(d) bonding said sheet to said substrate, selected conducting
stripes on said substrate being registered with selected conducting
stripes on said sheet; and
(e) connecting a tape-mounted semiconducting logic device and a
display device to said flexible substrate.
19. A method of manufacturing an electronic calculator comprising
the steps of:
(a) forming a pattern of conductive stripes on a flexible
substrate;
(b) connecting the leads from a tape-mounted semiconducting logic
device to selected conducting stripes on said substrate;
(c) connecting selected conducting stripes on said substrate to a
keyboard means; and
(d) connecting selected conducting stripes on said substrate to a
display device.
20. The method according to claim 19, wherein said flexible
substrate is a plastic material selected from the group consisting
of a polyester and polyimide plastics.
21. The method according to claim 19, wherein said display device
is also tape-mounted.
22. The method according to claim 19, wherein said flexible
substrate is provided by flexible plastic material and the pattern
of conducting stripes is formed on said flexible material at a
plurality of locations along a length of said flexible material,
whereby said pattern repeats along the length of said flexible
plastic material.
23. The method according to claim 22, wherein said display device
is also tape-mounted.
24. The method according to claim 1, wherein said flexible
substrate is provided by a length flexible material and the pattern
of conducting stripes is formed on said flexible material at a
plurality of locations along said length of flexible material,
whereby said pattern repeats along the length of said flexible
material.
25. The method according to claim 24, further including the step of
severing said substrate between said patterns and wherein the step
of folding said portion is accomplished prior to said severing
step.
26. The method according to claim 25, wherein said display device
is also tape-mounted.
Description
This invention relates to improvements in methods of manufacturing
an electronic calculator and specifically to the method of
manufacturing an electronic calculator using a flexible carrier.
Illustrative of the prior art methods of manufacturing an
electronic calculator are those methods which relied upon the use
of relatively rigid printed wiring boards, having conductors formed
thereon typically by subtractive technology and occasionally by
additive technology, with conventionally packaged semiconductor
devices, such as the dual-in-line package devices, mounted thereon
and a keyboard similar to those disclosed in U.S. Pat. No.
3,806,673 or U.S. patent application Ser. No. 644,206 filed Dec.
24, 1975. Additionally, in the prior art, it was not uncommon that
electronic calculators employed a plurality of discrete electrical
devices in addition to the one or more semiconductive devices. Also
in the prior art, relatively simple circuits, having, for instance,
a single semiconductive chip but, not having a keyboard or display
devices, have been implemented on a flexible carrier.
The prior art method of manufacturing an electronic calculator
utilizes components having relatively high costs and uses a method
associated with such components which is relatively labor
intensive, that is, requires a relatively large amount of human
effort. Recently, great strides have taken place in consolidating
the number of electrical devices into a minimum number of
semiconductor chips, thereby reducing the cost of the electronic
components in an electronic calculator. Relatively few advances,
however, have been made in the art of assembling these electronic
components, including a keyboard, into an electronic calculator.
The aforementioned advances in semiconductor chip technology have
resulted in decreasing the cost of manufacturing the electronic
calculator thereby making the electronic calculator more attractive
commercially.
In order further to increase the market for the electronic
calculators, it is necessary that the cost associated with
manufacturing be reduced. This can be accomplished by utilizing
improved methods of manufacture.
It is therefore one object of this invention to improve the method
of manufacturing electronic calculators.
It is another object of this invention to reduce the amount of
human effort involved in manufacturing an electronic
calculator.
It is yet another object of this invention to manufacture
electronic calculators according to a method adapted for mass
production.
It is still yet another object of this invention to utilize
electrical components or subcomponents adaptable for use in a mass
production method of manufacturing an electronic calculator.
The foregoing objects are achieved as is now described. Generally,
in accordance with a preferred embodiment of the invention, a
plurality of identical adherent conductive circuit patterns are
formed on a flexible insulative carrier, each of the patterns being
a predetermined arrangement of interconnective conductors, such as
that utilized in an electronic calculator. A keyboard is then
formed upon the carrier utilizing selected portions of the
conductors as key switch contacts by deforming the carrier in
selected areas to create a plurality of protuberances and folding
the portion of the carrier, for instance, that portion including
the protuberances, back generally on itself such that the
conductors forming the key switch contacts make electrical
connection when the associated protuberance is depressed. A
plurality of semiconductive devices (preferably tape-mounted)
including logic and display devices are then attached to the
carrier in proper registration with the conductors formed thereon.
The carrier can then be divided into separate calculator circuits,
including integral keyboards, which can then be installed in a case
and interconnected with a source of electrical energy to produce an
electronic calculator. This use of a carrier in the method of
manufacture makes the process readily adaptable for use with
machinery requiring less human effort than the prior art required,
thus resulting in lower production costs. The individual calculator
circuits may be automatically tested at several points in the
production process.
IN THE DRAWINGS
FIG. 1 is a perspective view of an electronic calculator embodying
the invention;
FIG. 2 is a composite illustrating the method of manufacturing an
electronic calculator disclosed herein;
FIG. 3 depicts a portion of the carrier upon which an electronic
calculator circuit is assembled showing the conducting strips
formed thereon;
FIG. 4a depicts a portion of the carrier upon which an electronic
calculator circuit is assembled, showing the conducting strips and
keyboard formed thereon;
FIG. 4b depicts an alternate embodiment of the carrier as depicted
in FIG. 4a;
FIGS. 5a and 5b are sectional side views through an indentation
formed on the carrier;
FIG. 6 depicts an insulating layer which may be used in forming the
keyboard on the carrier;
FIG. 7 is a sectional side view through two switches of a keyboard
formed in the carrier, as is shown in FIG. 4a;
FIGS. 8a and 8b show typical tape-mounted semiconducting
devices;
FIG. 9 depicts a calculator implemented on the carrier, separated
into individual units and ready to be installed in a case; and
FIG. 10 is an exploded perspective view of the calculator
implemented on a carrier being located in a calculator case and
interconnected with a source of electrical energy.
DETAILED DESCRIPTION
The calculator manufactured according to this invention is designed
primarily for use in a hand-held, battery powered, pocket-size
version as is generally shown in FIG. 1, although the invention is
operable with larger desk model calculators as well. The calculator
substrate or carrier, upon which the electronics comprising the
electronic calculator is disposed, is contained within a small
housing 25, typically of molded plastic, and includes a keyboard 26
having 10 decimal number push-buttons, 0 to 9, along with a decimal
point push-button and a plurality of function push-buttons such as,
for example, plus (+), minus (-), equals (=), multiply (.times.),
divide (.div.), clear (c), and the like. A display 27 is provided
in the form of matrices of light-emitting diodes (LED) e.g., 21
(FIG. 8b), liquid crystal devices (LCD), or the like. While the
calculator shown in FIG. 1 depicts a display having 8 digits plus a
9th "annotator" digit for minus sign, error or overflow, and 19
keyboard push-buttons it is understood that the numbers of such
digits and push-buttons are design choices.
Referring now to FIG. 2, there is shown, in representative form, a
mass production assembly or fabrication line for manufacturing an
electronic calculator circuit in accordance with the method herein
disclosed. A flexible substrate or carrier 10 is shown being
uncoiled from a coil 11; the carrier 10 may be, for example, an
organic film such as polyester sold under the trade name Mylar by
the Dupont Company or a polymide sold under the trade name Kapton
by the Dupont Company, and having a thickness of about 3-50 mils,
but preferably 5-10 mils. The carrier 10 is equipped with a series
of registration holes 13 (FIG. 3) disposed along one or both
margins of the carrier 10. The carrier 10 is caused to move along
the fabrication line by a series of sprocketed spindles 14 having
teeth (not shown) engaging the carrier registration holes 13 (FIG.
3). These registration holes 13 and spindles 14 help to position
the carrier precisely during subsequent manufacturing steps.
The first step in the fabrication process is depicted by Box 30 and
comprises forming conductor patterns on the carrier 10. Referring
to FIG. 3, a section of carrier 10 having registration holes 13
therein is depicted. An entire pattern 15, comprising the
conducting stripes 12 such as that used in one electronic
calculator, and a portion 16 of a similar pattern of conductors 12
are shown after being formed on the carrier 10, it being understood
that the carrier would typically contain a plurality of such
patterns 15. Methods of forming conductive strips 12 on a substrate
such as carrier 10 are well known in the art, for example
conducting strips 12 may be formed by selectively screening on a
conductive ink such as that sold under the trade name LTC 1000 by
Methode Development Co. or, for example, by adhesively laminating a
conductive layer, such as, for example, a layer of copper, applying
and imaging a layer of photoresist and subsequently etching away
the copper from all areas except where conducting stripes 12 are
desired to be located. In the preferred embodiment of this process,
however, the conducting strips 12 are formed on the carrier by hot
die stamping. To hot die stamp the pattern 15 of conducting strips
12 on the carrier 10, a sheet of a conductor, such as copper,
having a thickness of approximately 1 mil, is affixed with an
adhesive to the carrier 10 by using a die, cut with the desired
pattern 15, heated to a temperature of 85.degree. C to 130.degree.
C and pressed against the sheet conductor for 150 milliseconds to 3
seconds under approximately 200 psi pressure if the carrier is
polyester. These times, temperatures and pressure are exemplary
and, of course, other times, temperatures and pressures will be
found to be operable and within the spirit and scope of this
invention. A commercial grade polyester adhesive is applied either
to the carrier or the sheet conductor before the hot die stamping
operation. Hot die stamping is preferrable to either the use of
inks or substrative conductor etching because (1) it can be more
accurately controlled dimensionally than a screening process, e.g.,
the use of inks, and (2) it is more amenable to continuous
production line use than conductor etching which requires
submergence in chemicals for a comparatively long period of
time.
Referring again to FIGS. 2 and 3, the carrier including pattern of
conducting strips 12, according to step 31, have a group of
indentations 17 formed in the carrier 10. A cross sectional view
through the carrier 10 in the area of indentation 17 is shown in
FIGS. 5a and 5b, where FIG. 5a depicts a conducting strip 12
running perpendicular to the section and where FIG. 5b depicts a
conducting strip 12 running parallel to the section, as is shown in
FIG. 3. Conducting strips 12a in way of the indentation will
subsequently form keyboard switch contacts. The indentations 17 are
formed in the carrier preferably by thermally forming the carrier
10 with the desired indentation pattern at a temperature of
approximately 115.degree. C and under a pressure of approximately
30 lbs. per square inch in the event of the use of polyester
carrier material. Alternatively, the indentations 17 in carrier 10
can be formed by die forming, vacuum forming or cold forming.
As can be seen from FIGS. 3 and 4, part of the carrier 10 for each
pattern 15 is folded back in later steps to form a keyboard.
Depending on the configuration of conducting strips 12 formed in
this area, undesirable interconnections could result, unless, for
example, an insulating medium is used. In FIG. 3, reference C
denotes at least those areas which should be covered by an
insulating medium, such as, for example, screening a non-conductive
cement in place to prevent undesired connections occuring in the
keyboard conducting stripe pattern shown in that figure.
Alternatively, according to the numeral 32 step (FIG. 2), a thin
flexible insulating layer 18 (FIG. 6), which, for example, may be
from the same type of material as carrier 10 is made, having a
group of apertures 19 therein generally conforming to the locations
of the indentations 17 in the carrier 10, is affixed to the carrier
10. As is shown in FIG. 6, the insulating layer 18 with hole
forming apertures 19 is also provided with registration holes 13
along one or more of the margins thereof and comprises a long tape
of such insulating layers 18. The carrier 10 and the tape of
insulating layers 18 are brought in close proximity to each other
and the insulating layers 18 are attached such that the apertures
19 in the insulating layer 18 properly register with the
indentations 17 in the carrier 10. As the insulating layers 18 are
affixed to the carrier 10 they are individually cut from the tape
comprising the insulating layers 18, leaving the margin areas
containing the registration holes 13 behind as waste, if desired.
The insulating layers 18 are attached to the carrier 10, for
instance, by thermal or adhesive bonding.
While the use of a tape of insulating layers 18 is considered to be
the preferred method of manufacturing the calculator, the use of a
tape of insulating layers 18 or the use of an insulating medium at
Reference C areas may not be employed if, for example, conducting
strips 12 are formed on both sides of the carrier 10.
Referring again to FIG. 2, in step 33 the carrier 10 is cut along
Reference A as is shown in FIG. 4a for each pattern 15 (FIG. 3) of
conducting stripes and the portions of the carrier 10 containing
the group of indentations 17 are then folded along Reference B, as
is shown in FIG. 4a, and the surfaces coming in contact during the
folding operation are affixatively attached. The group of
indentations 17 now appear as a group of protuberances 17 as is
more clearly shown in FIG. 7.
In FIG. 7 a side sectional view through a keyboard switch contact
is shown wherein the carrier has been folded over, portions of the
insulating strips 12a and 12b forming switch contacts 12a and 12b,
and the indentations 17 now being turned over to appear as
protuberances 17. The carrier 10 portion containing the
protuberances 17 is affixatively attached to overlaid portions of
carrier 10 or insulating layer 18, as the case may be, by, for
instance, thermal or adhesive bonding. As an alternative
embodiment, the portion of the carrier 10 folded back at this step
may be provided with no indentations and the indentations may be
provided in the portion of the carrier 10 with which the folded
back portion mates.
In lieu of folding back a portion of the substrate during forming
the keyboard, a separate piece of flexible insulating sheet 24
having conductors affixed thereto may be bonded to carrier 10. The
indentations may be provided either in carrier 10 or sheet 24. This
embodiment is shown in FIG. 4b. We prefer to use a folded back
portion of the carrier 10 in forming the keyboard, however, to
alleviate any need for forming conductor interconnections between
the carrier 10 and insulating sheet 24.
The various conductive patterns and keyboards may then be tested,
accoding to numeral step 34, of FIG. 2, for example, by applying
electrical probes to selected conducting strips 12 and depressing
selected keys, formed by the protuberances 17 and associated switch
contacts 12a and 12b, to test for proper operation of the keyboard.
Should a keyboard on the carrier fail the test, the pattern 15 of
the carrier 10 enclosing the defective keyboard may then be marked,
for example, by punching a hole at a predetermined location in the
area of the pattern is so that subsequent assembly steps will not
be accomplished on an area of the carrier including a defective
keyboard.
Then, according to step 35 of FIG. 2, tape mounted semiconducting
logic devices 20 and display devices 21 (FIGS. 8a and 8b) are then
brought in close proximity to the carrier 10, the leads 24 of the
tape mounted semiconducting logic devices and display devices being
electrically connected to predetermined conducting strip contacts
12c or 12d (FIG. 3). The tape mounted semiconducting logic devices
20 and display devices 21 may comprise, for example, MOS logic
chips and LED's or LCD's. Tape mounted devices are well known in
the art and are disclosed in U.S. Pat. Nos. 3,689,991 and
3,763,404.
Using the tape mounted display services 21 depicted in FIG. 8b
generally required multi-layering of the conducting stripes in the
area of the display. Referring again to FIGS. 3 and 4a, in FIG. 3
the conductors in the area where the display devices are to be
mounted are shown before multi-layering. In FIG. 4a, the conductors
in the area where the display devices are to be mounted are shown
after multi-layering. Thus, the added conductors 14 pass over
selected conductors 12' without making an electrical connection.
This is accomplished, for instance, by screening down a
non-conductive element over the selected conductors 12' to inhibit
an electrical connection to the added conductors 14. Of course,
certain inter connections between the added conductors 14 and the
other conductors 12 or 12' in the area where the display devices
will be mounted are desired, so in those areas no non-conducting
cement is applied. The added conductors 14 may be formed, for
instance, by screening down a conductive ink such as that sold
under the trade name LTC 1000 by Methods Development Co. It should
be evident that use of the tape mounted display device having lead
carried different distances from the axis of the device, such as
the tape mounted display device disclosed by U.S. patent
application Ser. No. 678,102 filed Apr. 19, 1976, can eliminate the
need for using multi-layered conductors.
The tape mounted device leads 24 are elctrically connected to
selected portions of the conductive strips 12c and 12d (FIGS. 4a
and 4b) by, for example, ordinary soldering, reflow soldering, or
electrically conductive cement such as that sold under the
trademark Ablebond 773-2 BRS by Ablestik Labs, Ablestik Adhesive
Co., of Gardina, California. Soldering and reflow soldering are
processes well known in the art.
In using soldering processes, soldering must be performed
carefully, especially for a carrier 10 made from polyester which
typically does not withstand well temperatures exceeding
160.degree. C. Using a conductive cement has the advantage of
involving a lower temperature than soldering, but conductive cement
bonded semiconductive devices may require more time to bond than
solder bonded semiconductive devices and it further may be more
difficult to replace a conductive cement bonded semiconductive
device than a solder bonded semiconductive device, depending on the
cement selected. If the aforementioned cement is utilized however,
faulty components can be removed with a heated knife.
Additionally, when devices 20 and 21 are electrically connected to
the conducting strips 12c and 12d, as aforementioned, excess
portions of the tapes 22 and 23, for instance, those portions
containing the registration holes 13, are cut away and discarded.
In order to help assure that a malfunctioning semiconducting device
is not electrically connected to the conducting strips making up a
functioning keyboard and conductor pattern, devices 20 and 21
supported by tapes 22 and 23 may be pretested, and malfunctioning
devices marked in such a manner that they will not be electrically
connected to the conducting strips 12c and 12d. This marking may be
accomplished, for instance, by punching a hole in the tape 22 or 23
near the malfunctioning device, which hole is sensed by machinery
bringing the tapes 22 and 23 into close proximity with the carrier
10, causing the machinery to skip and discard the malfunctioning
device.
Referring again to FIG. 2, at step 36, as each device 20 and 21 is
affixed, the circuit on the carrier 10 is tested assuring that each
device is being properly integrated onto the carrier 10. Should a
circuit mounted on a portion of the carrier 10 fail a test, the
aforementioned marking technique may be again employed to signal to
machinery down the fabrication line that the calculator circuit
associated with the mark is inoperable. This testing step may be
accomplished after each device 20 and 21 is attached to the carrier
10 or may be accomplished after all devices have been attached.
As is shown at step 37 in FIG. 2, after all the circuit components
have been integrated onto the carrier as aforementioned, the
carrier is separated into individual calculator circuits and
malfunctioning units segregated from operating units, using the
aforementioned marks to key the segregation. Methods for
accomplishing such separation and segregation are well known or
evident to one trained in the art. A calculator circuit implemented
on carrier 10, as separated into an individual unit and having
margin areas containing registration holes removed, is shown in
FIG. 9.
The registration holes 13, shown in the various carriers 10, tapes
22 and 23 and layers 18, make the process disclosed automable and
make the positioning of devices 20 and 21 and the layers 18
controllable to a pecision necessary to assure proper registration
between the leads 24 on the tapes 20 and 21 and the conducting
strips 12c and 12d on the carrier 10 and between the apertures 19
in the layers 18 and the indentations 17 in the carrier 10. The
movement and registration between the aforementioned components is
controlled, for instance, by spindles 14 associated with machinery
handling the carrier 10, tapes 20 and 21 and the tape of insulating
layers 18. Only the spindles 14 associated with the carrier 10 are
shown in FIG. 2.
As can be seen from FIGS. 3, 8a and 8b, the orientation of devices
20 and 21 on the tapes 22 and 23 and the orientation of the
predetermined conducting strip contacts 12c and 12d suggest that
the paths of the tapes 22 and 23 could be disposed at right angles
to the path of the carrier 10. Proper registration between the
leads on the devices 20 and 21 and the strip contacts 12c and 12d
does not depend on the fact that the tapes 22 and 23 approach the
carrier 10 at a right angle; the tapes 22 or 23 may approach the
carrier 10 from a direction parallel to the path of the carrier 10
(or another angle), for instance, so long as the respective devices
20 and 21 are properly oriented thereon. Similarly, the direction
which the tape of insulating layers 18 approaches the carrier 10 is
not critical.
After separation the circuits are readily installed in a case 25
and connected to a source of electrical energy such as means for
connection to a battery or to conventional AC power, thereby
completing an electronic calculator. Referring now to FIG. 10,
there is shown an exploded view of the calculator manufactured on a
flexible carrier 10 being disposed in a case 25, having by
pushbuttons 26 forming a keyboard in conjunction with the
protuberances 17 and associated switch contacts 12a and 12b (FIG.
7) disposed on carrier 10. The circuit formed on carrier 10 is
interconnected with leads 28 connecting with battery connector 29.
Leads 28 may be interconnected with selected conducting stripes 12,
for instance, by soldering, reflow soldering or a conductive
cement. The calculator case 25 should include a keyboard support
surface 29 for supporting the key switches during switch operation.
The calculator case 25 may include means such as support surface
38, for disposing that portion of the carrier 10 including the
display devices 21 at an angle to the portion of the carrier
including the keyboard to improve the viewability of the display 21
to an operator.
Having described the invention in connection with certain specific
embodiments thereof, it is to be understood that further
modification may now suggest itself to those skilled in the art. It
is understood that the invention is not to be limited to the
specific embodiments except as set forth in the appended
claims.
* * * * *